function cc=fun(x,n)
m=length(x);
k=1;
if (mod(m,n)~=0)    
   warning( 'n is wrong')
  else
    for i=1:m/n
      for j=1:m/n
         c_{k}=x(1+n*(i-1):n*i,1+n*(j-1):n*j);
    k=k+1;
    end
  end
  cc=c_;
end
